Add project settings to toggle Steam time tracker.

[bruvzg]

Adds project setting to disable SteamAPI library loading for specific project.

See #113868

[akien-mga]

This would help with #113868 but it would disable time tracking for GodotSteam users, which may not be desirable, though it's probably not too bad.

I wonder if another option would be for the setting to define which lib to load (with a path) and let GodotSteam override it with its own.

[bruvzg]

I wonder if another option would be for the setting to define which lib to load (with a path) and let GodotSteam override it with its own.

I guess we can add this instead (or both), I assumed GodotSteam will load own version (and this was causing conflicts), and if it does, time tracking should still work, but have not checked it.

[bruvzg]

Added path override property as well.